How to find a good app builder company?

I belong from Chicago and I am running my own clothing business which is just not selling clothes items but it is also giving opportunities to designers to join our team and design clothes. It’s been 30 years since I have built this business. Now after this years of experience I want to spread my business globally. I am looking for some mobile app builder companies which can help me to develop my own app through which I can spread my business roots and boost up my business globally. Can anyone suggest me any good company for application building?
Source: https://appdevelopmentagency.com.au/